1. Field of the Invention
The present invention relates to an optical disk drive which accesses an optical disk, such as CD-R (compact disk-recordable) or CD-RW (compact disk-rewritable), an optical recording control method which controls the optical disk drive, and a data processing apparatus in which the optical disk drive is provided.
2. Description of the Related Art
Generally, the information on optical disks, such as CD (compact disk), is recorded along tracks, which may be concentric rings of a certain width provided for the innermost track to the outermost track. Typically, a track is a narrow annulus at some distance from the disk center. The track pitch is the center-to-center distance between neighboring tracks. The information is recorded on the optical disks, including CD-R (compact disk-recordable) and CD-RW (compact disk-rewritable), at a constant linear recording density.
There are two major methods that carry out recording/reproducing of an optical disk, such as CD-R or CD-RW: one being called CLV (Constant Linear Velocity) method and one being called CAV (Constant Angular Velocity) method. Moreover, ZCLV (Zone CLV) method is known as a disk recording/reproducing method improving the CLV method. For example, see Japanese Laid-Open Patent Application Nos. 11-296858, 2000-11384, 2000-48484, 7-21585, 9-231580, 9-270129, 10-79124 and 11-66726.
In the case of the CLV method, the disk is rotated at a constant linear velocity, and the amount of information recorded on the disk is maximized whereas the data management and the disk rotation control in a complicated manner are performed. In the case of the CAV method, the disk is rotated at a constant angular velocity, and the data management and the disk rotation control may be easily performed whereas the amount of information recorded on the disk is decreased relatively from the maximum level of the CLV method.
In the case of the ZCLV method, the optical disk is divided into a number of zones. For each of the zones of the disk, the data management and the disk rotation control are performed with the constant linear velocity being kept, similar to the CLV method. The larger the disk rotation speed becomes, the outer the location of one of the zones on the disk is.
Recently, the CLV method is frequently used as the method for recording/reproducing of optical disks such as CD-R and CD-RW. Several optical disk drives that are based on the CLV method with the recording linear velocity being increased to higher values are commercially available. Further, optical disk drives that are based on the CAV method with the ease of the data management and the disk rotation control utilized, or based on the ZCLV method, will be commercialized. When the CLV-based medium, such as CD-R or CD-RW, is rotated at a constant angular velocity based on the CAV method, the linear velocity of a track on the disk varies to a larger value as the radius of the track around the disk center increases.
Although the development of optical disk drives with high recording linear velocity is put forward, there is the possibility that poor-quality optical media, which may be also commercially available, be used with the optical disk drives.
Normally, in a conventional optical disk drive, prior to the start of recording, an optical power calibration (OPC) is performed for a power calibration area (PCA) at the innermost location of the disk, in order to determine the optimum recording power. If a poor-quality optical disk is placed on the optical disk drive, the OPC is performed on the optical disk drive for the PCA of the poor-quality optical disk. When the OPC is performed with the poor-quality optical disk at a high recording speed that is 16 times higher than the double speed (which ranges from 1.2 m/s to 1.4 m/s), the servo control of the PCA of the disk does not follow in accordance with the recording track and an OPC error is likely to occur. As described earlier, in an optical disk drive based on the CAV method, the linear velocity of the track on the disk varies to a larger value as the radius of the track increases. In such a case, the OPC error is more likely to occur. If an OPC error occurs, it is difficult for the conventional optical disk drive to determine the optimum recording power prior to the start of recording. Hence, the conventional optical disk drive cannot start performing the recording of the optical disk because of the occurrence of an OPC error.
For example, Japanese Laid-Open Patent Application No. 9-305973 discloses an optical disk drive in which the optimum recording power is determined by performing an optical power calibration (OPC) at the outer peripheral portion of a user area of the disk. However, the conventional optical disk drive of the above document does not take into consideration countermeasures against an OPC error when the OPC is performed with a poor-quality optical disk at a high recording speed.
The optimum recording power for the laser diode of the optical pickup increases in proportion to changes of the linear velocity of the disk when performing the CAV method or the ZCLV method. If the recording power is kept constant, the recording of information in the disk at the outermost track using the optimum recording power is impossible. To avoid this, the optimum recording power, which is determined through the OPC, is adjusted in accordance with the linear velocity of the disk at the track of concern to be recorded. However, when using the laser diode of the optical pickup with its maximum output power being relatively low, or when using the poor-quality optical disk with a relatively low recording sensitivity, the optimum recording power that is determined through the OPC may exceed the maximum output power of the laser diode. In such a case, the conventional optical disk drive cannot continue performing the recording operation of the optical disk at the high recording speed.